Amazon UK became the first business to issue such a warning. It was given at a meeting on Friday organised by Dominic Raab, the Brexit secretary.

Doug Gurr, UK manager for the American online giant, told the other guests, who included representatives of Britain’s biggest businesses, that this worst-case outcome formed part of his contingency planning.

The remark stunned those present, with some expressing scepticism about Amazon’s forecast.

An Amazon spokesman declined to confirm or deny the comments but said: “Like any business, we consider a wide range of scenarios in planning discussions so that we’re prepared to…

Want to read more?

Subscribe now and get unlimited digital access on web and our smartphone and tablet apps, free for your first month.